The magnitude 7.8 earthquake began 15 kilometres north-east of the small farming settlement of Culverden, roughly 60 kilometres south-west of Kaikoura. From the initial rupture on the Humps Fault, energy cascaded northward through a chain of faults that geologists had never expected to fail together. The Kekerengu Fault displaced by the greatest amount. The Hundalee Fault moved both vertically and horizontally. A previously unknown fault in Waipapa Bay revealed itself mid-rupture. The Hope Fault, long considered New Zealand's most active, shifted along its seaward segment, while the offshore Needles Fault extended the damage beneath the sea. Cape Campbell, at the north-eastern tip of the South Island, lurched more than two metres to the north-north-east and rose almost a metre, physically narrowing the gap to the North Island. Kaikoura itself moved nearly a metre to the north-east and rose 70 centimetres. Even distant Christchurch shifted two centimetres to the south.

By dawn, Kaikoura was an island on land. Landslides had buried State Highway 1 in both directions. The Main North Line railway, a critical freight link between Wellington and Christchurch, was severed. The Inland Kaikoura Road was impassable. With roads blocked, bridges shattered, and the rail line out, every land route into town had been erased. Two people had lost their lives: a man crushed when the historic Elms Farm homestead collapsed near Kaikoura, and a woman killed by a head injury at Mount Lyford. The navy vessel HMNZS Canterbury arrived on 16 November and evacuated roughly 450 people to Lyttelton, eventually bringing the total to more than 900. The RNZAF dispatched NH90 helicopters and a C-130 Hercules, while a visiting U.S. Navy P-3 Orion and two Japanese Kawasaki P-1 patrol aircraft, in New Zealand for the navy's 75th anniversary, were redirected to help.

Though the epicentre lay hundreds of kilometres to the south, Wellington bore the economic brunt. Two-thirds of the total NZ$2.27 billion in insurance losses fell on the capital region. Buildings that had been constructed within the previous decade failed: BNZ Harbour Quays, opened in 2009, was demolished by 2019. Statistics House, built in 2005, was condemned. The 54-year-old former ICI Building at 61 Molesworth Street came down within weeks. The earthquake rewrote how New Zealand assessed building safety, producing the "Red Book" seismic guidelines in 2017 and its revised "Yellow Book" chapter in 2018. Wellington Central Library, undamaged during the quake itself, was suddenly closed in March 2019 after engineers reassessed it under the new understanding of how concrete buildings actually perform when shaken.

Along the Kaikoura coastline, the seabed rose by as much as six metres in places, exposing the intertidal zone to air and sunlight. Vast beds of Durvillaea bull kelp, the foundation of the local marine ecosystem, died in the sudden uplift. The earthquake also buried one of only two boulders known to harbour the eyelash seaweed, a species that has not been found in the wild since, and may now be extinct. Yet the ocean began recovering faster than expected. Genomic studies showed that the original Durvillaea populations survived offshore and were recolonising the newly formed coastline. Meanwhile, 850 million tonnes of sediment avalanched through the Kaikoura Canyon in a massive submarine landslide, sending a turbidity current more than 600 kilometres along the Hikurangi Channel.

Rebuilding was measured in years, not months. The Inland Kaikoura Road reopened with restrictions in late November 2016 and fully on 19 December. State Highway 1 south of town followed two days later, but the northern section did not reopen until 15 December 2017, more than a year after the quake. The complete Picton-to-Christchurch rail link was not restored until September 2017, and passenger trains did not run again until December 2018. The final rebuild of road and rail between Clarence and Oaro, completed in late 2020, cost NZ$1.25 billion alone. For a town that depends on tourism, the isolation was devastating. Small operators went under without visitors. Farmers could not move their produce. The fishery closed over contamination fears. Even three cows, stranded on an island of earth after the surrounding ground collapsed, became unlikely international celebrities. Kaikoura endured, rebuilt, and eventually welcomed the world back.